苹果官方文档https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html

demo

- (void)testEncodeChar
{
    NSLog(@"int              : %s", @encode(int));
    NSLog(@"int *            : %s", @encode(int*));
    NSLog(@"unsigned int     : %s", @encode(int));
    NSLog(@"float            : %s", @encode(float));
    NSLog(@"float *          : %s", @encode(float*));
    NSLog(@"char             : %s", @encode(char));
    NSLog(@"char *           : %s", @encode(char *));
    NSLog(@"BOOL             : %s", @encode(BOOL));
    NSLog(@"void             : %s", @encode(void));
    NSLog(@"void *           : %s", @encode(void *));
    NSLog(@"NSString *       : %s", @encode(NSString *));
    NSLog(@"NSObject *       : %s", @encode(NSObject *));
    NSLog(@"NSArray[]        : %s", @encode(typeof(@[@"str"])));
    NSLog(@"id               : %s", @encode(id));
    NSLog(@"NSObject         : %s", @encode(NSObject));
    NSLog(@"[NSObject class] : %s", @encode(typeof([NSObject class])));
    NSLog(@"NSError **       : %s", @encode(typeof(NSError **)));
    int intArray[5] = {1, 2, 3, 4, 5};
    NSLog(@"int[]            : %s", @encode(typeof(intArray)));
    float floatArray[3] = {0.1f, 0.2f, 0.3f};
    NSLog(@"float[]          : %s", @encode(typeof(floatArray)));
    
    typedef struct _struct {
        short a;
        long long b;
        unsigned long long c;
    } Struct;
    NSLog(@"struct       : %s", @encode(typeof(Struct)));
}

2018-01-14 14:26:49.855018+0800 WiOSDemo[82490:45356764] int              : i
2018-01-14 14:26:49.855146+0800 WiOSDemo[82490:45356764] int *            : ^i
2018-01-14 14:26:49.855231+0800 WiOSDemo[82490:45356764] unsigned int     : i
2018-01-14 14:26:49.855344+0800 WiOSDemo[82490:45356764] float            : f
2018-01-14 14:26:49.855451+0800 WiOSDemo[82490:45356764] float *          : ^f
2018-01-14 14:26:49.855545+0800 WiOSDemo[82490:45356764] char             : c
2018-01-14 14:26:49.855659+0800 WiOSDemo[82490:45356764] char *           : *
2018-01-14 14:26:49.855739+0800 WiOSDemo[82490:45356764] BOOL             : B
2018-01-14 14:26:49.855809+0800 WiOSDemo[82490:45356764] void             : v
2018-01-14 14:26:49.855906+0800 WiOSDemo[82490:45356764] void *           : ^v
2018-01-14 14:26:49.855984+0800 WiOSDemo[82490:45356764] NSString *       : @
2018-01-14 14:26:49.856064+0800 WiOSDemo[82490:45356764] NSObject *       : @
2018-01-14 14:26:49.856159+0800 WiOSDemo[82490:45356764] NSArray[]        : @
2018-01-14 14:26:49.856288+0800 WiOSDemo[82490:45356764] id               : @
2018-01-14 14:26:49.856478+0800 WiOSDemo[82490:45356764] NSObject         : {NSObject=#}
2018-01-14 14:26:49.856661+0800 WiOSDemo[82490:45356764] [NSObject class] : #
2018-01-14 14:26:49.856841+0800 WiOSDemo[82490:45356764] NSError **       : ^@
2018-01-14 14:26:49.856971+0800 WiOSDemo[82490:45356764] int[]            : [5i]
2018-01-14 14:26:49.857150+0800 WiOSDemo[82490:45356764] float[]          : [3f]
2018-01-14 14:26:49.857298+0800 WiOSDemo[82490:45356764] struct       : {_struct=sqQ}

问题一

// 通过NSInvocation，怎么调用下面这个函数？
- (NSString *)testParamForcharValue:(char)charValue//c
                  unsignedCharValue:(unsigned char)unsignedCharValue//C
                         shortValue:(short)shortValue//s
                 unsignedShortValue:(unsigned short)unsignedShortValue//S
                           intValue:(int)intValue//i
                   unsignedIntValue:(unsigned int)unsignedIntValue//I
                          longValue:(long)longValue//l
                  unsignedLongValue:(unsigned long)unsignedLongValue//L
                      longLongValue:(long long)longLongValue//q
              unsignedlongLongValue:(unsigned long long)unsignedlongLongValue//Q
                         floatValue:(float)floatValue//f
                        doubleValue:(double)doubleValue//d
                          boolValue:(BOOL)boolValue//B
                      selectorValue:(int(^)(int, int))selectorValue//:
                          rectValue:(CGRect)rectValue//{name=type...}
                          sizeValue:(CGSize)sizeValue//{name=type...}
                        charPointer:(char *)charPointer//*
                              point:(int *)pint//^
                         classValue:(Class)classValue//#
                      nsstringValue:(NSString *)nsstringValue//@
                       nsarrayValue:(NSArray *)nsarrayValue//@
                            idValue:(id)idValue//@;
                        rectPointer:(CGRect *)rectPointer
{
    NSLog(@"2 + 3 = %d", selectorValue(2, 3));
    pint += 1;
    *rectPointer = CGRectMake(100, 1000, 10000, 100000);
    return @"return string";
}

参考连接：https://www.jianshu.com/p/a4d0d3346afe

问题二

// 通过NSInvocation，怎么调用一个任意参数和任意返回值的函数？